With its diverse blend of concept cars, luxury rides and economic vehicles, New York’s auto show usually puts some zing into the auto show circuit. This year’s show, with its focus on muscle and power, signified nothing less than the end of an era for some who attended its preview days last week.

“Everyone is talking about how this show is irrelevant because it’s all about muscle cars," said John Wolkonowicz, senior markets analyst at Global Insight’s Automotive Group. "But it’s not because we are witnessing the end of an era that will be remembered fondly for years to come."

Chrysler’s 2009 Dodge Challenger was a centerpiece of the New York show, a reinvention of Dodge’s iconic muscle car meant to appeal to baby boomers with the cash to indulge their nostalgic fantasies. It goes up against the recently reissued Ford Mustang and the new Chevrolet Camaro, another redeveloped muscle car that’s due in dealer showrooms in early 2009.

There was even more retro brawn on show as Pontiac revealed a pickup truck-muscle car combination that hearkens back to the classic El Camino coupe utility vehicle that Chevy stopped building in 1987. The as-yet-unnamed car — essentially an Australian Holden “Ute” — is expected to make its U.S. debut next year.

These historic cars may make auto enthusiasts’ hearts flutter, but they’re entering a dying market for muscle cars, according to Wolkonowicz.

The revived Challenger and Camaro are a “last hurrah” for high-horsepower, brawny muscle cars, Wolkonowicz said. The industry is moving toward compliance with an energy bill passed in December that requires automakers to achieve a fleet fuel-economy standard of 35 miles per gallon by 2020, he noted, and automakers are struggling to find ways to squeeze more mileage out of their biggest, least fuel-efficient vehicles.

“In some ways the current situation reminds me of the early 1970s when the industry reached its last peak in performance and the government last got involved in regulating the industry," Wolkonowicz said. "Cars became emasculated, and I don’t have fond memories of models made between 1975 and 1995. I don’t think the industry will repeat that period, but we have recently enjoyed a level of performance that we’re never seen before, and that’s going to change.”

Automakers will continue to make high-performance cars, but they’ll be powered by new propulsion systems or using new high-performance gas engines, such as Ford’s “EcoBoost,” which uses 20 percent less fuel than today’s similarly powerful engines. But these innovations will be costly and take time to become widespread, he added.

“There’s no free lunch here,” he said. “The price of these vehicles will go up and they’ll cost more to maintain. We can still have performance cars, but we’ll have them with hybrid engines and smaller fuel-injection motors, and they won’t have the same visceral impact of today’s muscle cars. It will be different, but we’ll get used to it.”

Over the past decade even run-of-the mill sedans have become increasingly powerful, Wolkonowicz said, noting that today’s humble Honda Accord could outpace most of the famous muscle cars of the 1960s.

But Americans appear to be losing their appetite for sporty, retro-styled cars, according to Tom Appel, editor of Consumer Guide Automotive, which offers buying advice to car shoppers.

While the relaunch of the Ford Mustang in 2005 boosted sales to an annual rate of 200,000 units, these days the Mustang would do well to reach 100,000, he said. And the new Ford Thunderbird, Volkswagen Beetle and Pontiac GTO have all failed to reach impressive sale numbers.

What’s more, 12 sport coupes have been killed off in the last six years, including the Honda Prelude, the Toyota Celica and the Acura RSX. Toyota is expected to kill off the Solara in the next few years, Appel added.

While the introduction of the Challenger and the Camaro may boost interest in retro muscle cars, the novelty is likely to wear off soon, Appel added.

“There will be some initial interest in the Challenger and the Camaro because of the warm, fuzzy nostalgia associated with them and it will probably bring the market to a new high, but it will be short-lived,” Appel said. “I can’t see them reshaping or expanding what is already a small market.”